Biosensors provide rapid data containing information on molecular interactions that are not easily available using equilibrium assays or histochemical methods. This study will be the first of a series with long-term objectives of developing rapid biosensor methods applied to extracts of breast cancer biopsies for (1) predicting risk of recurrence in both node negative and node positive breast cancers, (2) recognizing the presence of previously unidentified ERE-binding components in tumors, and (3) obtaining information leading to selection of effective therapeutic treatment modalities having a high likelihood of success for a given individual's breast cancer. As the first of the series, this study focuses primarily on establishing novel biosensor methods, which correlate with prognostic information for the cancer represented in extracts of tumor tissue biopsies. The proposed methods utilize IA, Inc.'s biosensor technology in conjunction with the extensive tumor bank and associated records, and resources for receptor preparation and assay at the University of Louisville. Specific aims are: (1) Use antibody-based sensors to assess established tumor markers in breast cancer biopsy extracts, (2) Assess capacity of selected tumor extracts of high risk and low risk node negative and node positive biopsies to compete with standardized hER preparation for binding to sensors bearing various EREs. ERE sequences found upstream of the promotor region of genes having known relevance to processes of tumorigenesis will be used. Included will be genes for proteins found in breast cancers, which have been associated with prognosis for patient response to Tamoxifen treatment, such as cathepsin D and pS2, and genes for transcription factors h-fos and jun. (3) Correlate the biosensor results with data from electrophoretic mobility shift and supershift assays and with retrospective analysis of patient characteristics and clinical follow-up. (4) Compare binding of tumor extract to ERE fibers with and without 4-OH-tamoxifen and correlate results with treatment outcome data. This novel approach with miniaturized biosensor techniques holds promise for rapid assessment of tumor markers and discovering new cancer associated regulatory proteins of clinical significance. It could reveal previously unrecognized ERE-binding proteins in tumors, and will lead to a biosensor product, which is an improved method for identifying treatment modalities most likely to produce a positive outcome for an individual cancer. Phase II studies will expand the sample base and will include a broader range of antibodies for tumor marker identifications. Co-activator and co-repressor interactions as well as ERE and other response element interactions will be included. Previously unidentified ERE binding-components will be characterized. If the 4-OH-tamoxifen sensor data correlates well with treatment outcome, additional therapeutic agents will be similarly assessed.